Cordocentesis

Although this antenatal test is done after 20 weeks' gestation, the results are ready in a couple of days and it is the only way to detect some conditions. It is a test usually reserved for women with a known family history of certain disorders, for example cystic fibrosis, some chromosomal problems, and hereditary blood disorders.

Sometimes referred to as fetal blood sampling, the baby's blood sample is taken from the umbilical cord (guided by ultrasound). White blood cells from the sample are cultured and tested. There is a risk of miscarriage with this test (between 1 and 2 per cent) and it is not widely available in the UK, although if necessary it is possible to be referred to a private clinic which performs this test.


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